The present invention relates to the collection of airborne or aqueous organic compounds, particularly to the collection of chemical warefare (CW)-related compounds, and more particularly to a collector for such organic compounds which is provided with carbon nanotubes whereby extraction and retention efficiencies is greatly increased over conventional airborne or aqueous compound collection approaches.
Since the accidental discovery of carbon nanotubes about a decade ago, carbon nanotubes have displayed a considerable number of unique properties. Researchers have found carbon nanotubes to be stronger and tougher than steel, capable of carrying higher current densities than either copper or superconductors, and able to form transistors only a few nanometers wide. Unlike diamond and graphite, which are both insulators, a remarkable property of carbon nanotubes is their ability to act as either a metal or semiconductor. Applications range from future ultrasmall electronic circuits, to ultrathin CRTs, to bullet proof armor, gas storage, air filter units, etc. In addition, the carbon nanotubes can be doped so as to absorb hydrogen, for example, with a sorption-desorption cycle than can be repeated with little decrease in the sorption capacity.
Derived from spheroidal fullerness (xe2x80x9cBuckyballsxe2x80x9d), a carbon nanotube is a long and hollow array of hexagonal-pattern carbon atoms. Similar to a single layer of graphite rolled into a tube, carbon nanotubes are typically 2 nm in diameters and several hundred micrometers long.
While carbon nanotubes have been considered for many applications, as pointed out above, little prior effort has been focused on the chemistry of the carbon nanotubes as collectors and concentrators of target compounds in air, water, or waste streams. The present invention is directed to utilizing carbon nanotubes as collectors and concentrators of organic compounds in air, water, or waste streams, particularly CW-related vapor collections and concentrations, such as CW surrogates dimethylmethyl-phosphonate (DMMP), diisopropyl-aminaethanol (DIEA), and diisopropylmethylphosphonate (DIMP).
It is an object of the present invention to provide carbon nanotube coatings as chemical absorbers.
A further object of the invention is to provide airborne or aqueous organic compound collectors and concentrators utilizing carbon nanotubes.
A further object of the invention is to provide collectors for airborne chemical warefare-related compounds using carbon nanotubes.
Another object of the invention is to provide organic compound collectors having carbon nanotubes.
Another object of the invention is to provide carbon nanotube coatings on an airborne organic compound collector.
Another object of the invention is to provide an airborne collector with a carbon nanotube coating for collecting and concentrating chemical warefare-related organic compounds.
Other objects and advantages of the invention will become apparent from the following description and accompanying drawing. Basically, the present invention involves providing an airborne or aqueous organic compound collector with a coating of carbon nanotubes. Collectors using carbon nanotubes have been shown to be four-ten times more effective toward concentrating a chemical warefare (CW) surrogate than the currently utilized optimized carbonized polymers, such as Carboxen made by Sepelco (Aldridge/Sigma), for CW-related vapor collections.
The carbon nanotubes, as pointed out above, are typically 2 nm in diameter and several hundred micrometers long, and can be coated on a metal substrate, which for example, may be a disc or honeycomb, made of metal, plastic, and ceramics by suspending the nanotubes uniformly in a solvent containing a binder, for example, an oryanosilane such as polydimethylsilane, and then applying such to the substrate via ultrasonic impulses to a spray apparatus. More simply, but less effectively, a substrate, such as a 1 cm metal disk can be uniformly airbrushed with a solution containing the carbon nanotubes. Exposure of the carbon nanotube-coated disks to controlled atmospheres of CW-related compounds revealed very superior extraction and retention efficiencies compared to the currently utilized Carboxen.